Author Topic: Snubber guide lines  (Read 11367 times)

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Offline peranders

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Snubber guide lines
« on: June 08, 2005, 09:19:18 AM »
Notice that I will edit this post if somebody can come up with better reasons for adding a snubber in power supplies.

1 Keep it compact in order to reduce stray inductances

2 Locate the cap combination as close as possible to the current consumer (amp)

3 Reasonable values: 100 uF// 100n as some average but may be increased or decreased.

4 Suitable resistor values 0.1 ohms as a very minimum and 0.5-3 ohms as "normal". Power rating 0.6 W metal film but 1-2 W is also OK. The resistor should be low inductance and have good HF properties. You can also use surface mounted parts but beware or the rated power.

5 The snubber package should be 100 uF(22-220 uF) in parallel with 10-100 nF + resistor. You should not add an unsnubbed single plastic/ceramic cap IF you want the snubber to really work.


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As soon as you have a capacitor combination consisting of a rather good cap like 100 nF polyester and this cap is in parallel with an electrolythic cap you will need a snubber to reduce resonance peaks. You will not be able to reduce the dips though. Is this important? It depends. It is really important in switch applications in order to reduce harmonics and increase the effeciency.

Is it important in linear applications? Yes, if the amp is fast it may be important but snubberisated power supplies are extremely rare, almost never seen in high-end equipment and certainly not in consumer amps.

A trend and a fashion is started by Carlos Filipe Machado, carlosfm, over at www.diyaudio.com (EDIT rather forgotten these days 2009)

Maybe snubbers are here to stay or maybe they will be forgotten soon.

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If you happen to have a regulator the same things may apply but ask yourself why you want to have a snubber. When you have the answer you also know what to do. The problem is when you don't have so much knowledge in electronics, then it's really hard to deside. The best you can do is the read the datasheet for the regulator inmind and particulary the sections about decoupling and transient response and how to optimize it.

Is it for reducing resonances above 1 MHz?

Is it for creating perfect or at least good transient response when you apply signals way over 20 kHz?

Not knowing the importance of the snubber I have implemented this in my new super regulator power supply JSR06.
« Last Edit: March 22, 2009, 09:07:46 AM by peranders »
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Offline Sigurd Ruschkowski

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Snubber guide lines
« Reply #1 on: June 08, 2005, 09:37:36 PM »
Do you maybe have some schematics and simulations?



Sigurd

Offline peranders

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« Last Edit: September 21, 2008, 10:50:24 PM by peranders »
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